1. Field of the Invention
The present invention relates to a method of quantizing a color space, and more particularly, to a method of quantizing a HMMD color space.
2. Discussion of the Related Art
Generally, color information is an important information for display of images and for use in applications such as a content based image searching. However, the number of colors which can be displayed by a computer is limited. Therefore, maintaining a number of optimal colors required to store and process data becomes important in displaying colors. Accordingly, quantization maps M number of colors to N number of colors, where M greater than N, to obtain an optimal number of colors.
In computers, a color is expressed utilizing an RGB color model based upon the three primary colors of red R, green G, and blue B. Because a limitation exists in expressing the color changes such that the change can be sensed by the human eye, the RGB space is often converted into a user oriented HVC color model based upon a hue H, value V, and chroma C then converted back to the RGB space by quantization. Accordingly, various methods utilizing the HVC color space coordinates for a content-based image retrieval engines (or application program) have been provided in the related art.
However, change of color with low chroma such as black, white and gray depends on brightness while change of color with high chroma depends on tint, shade and chroma. Thus, quantization of the HVC performs well within a pure color space having high chroma, but has problems in decolored space having low chroma.
Accordingly, an object of the present invention is to solve at least the problems and disadvantages of the related art.
An object of the present invention is to provide a quantization method for obtaining an optimal number of colors.
Another object of the present invention is to provide an efficient quantization method for the HMMD color space.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the scheme particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a method of quantization a HMMD color space according to the present invention includes selecting a plurality of parameters defining a three-dimensional color space and linear-quantizing or nonlinear-quantizing the defined color space based on at least one of the selected parameters.
Another embodiment of the method for quantization a HMMD color space according to the present invention includes determining a parameter for linear-quantizing or nonlinear-quantizing of a color space based on a boundary threshold value.